Generally, the present application relates to radio-frequency identification (“RFID”) techniques in an ultra-low temperature (“ULT”) environment.
A ULT cold-storage device may store items (for example, vials that include temperature sensitive samples) at a temperature such as approximately −80° C. This temperature may be used for preventing degradation long-term or provide substantially indefinite storage of temperature sensitive items (for example, biological samples stored in vials).
A ULT cold-storage device may be able to hold a relatively large number of items that are in containers (for example, approximately 20,000 1 μl vials). Due to such significant storage capacity, it may be desirable to track inventory of items by maintaining a log of the given samples in a given ULT freezer.
One conventional way to track inventory employs attaching or connecting an RFID tag to stored items and/or containers (for simplicity, the term “item” encompasses the term “container” herein unless specifically indicated otherwise). As the items are placed in or removed from the ULT cold-storage device, the tags on the items can be scanned with an RFID reader to electronically identify the items outside of the ULT cold-storage device. Before items are added to the ULT cold-storage device, a given item's RFID tag can be read and the inventory list contained in the ULT cold-storage device can be updated (or alternatively, initially generated) by adding the item's information to the list. Similarly, as items are removed from the ULT cold-storage device, the RFID tag can be read, and the inventory list can be updated (or alternatively, initially generated), by removing the item's information from the list. This technique, however, requires a user in a labor intensive manner to perform a manual RFID reading step every time an inventoried item is added or removed from the ULT cold-storage device. Failure of the user to perform this RFID reading step can cause errors in the inventory list for the ULT cold-storage device. Further, by the user performing the scan and update steps repeatedly, miscommunications, miscues and other problems regularly occur causing significant inventory control errors, greater difficulty in inventory logistical planning, increased delays in inventory restocking, among others.
Another way to track RFID-tagged items is to have one or more RFID reader antennas in the ULT cold-storage device. However, due to accuracy limitations, known cold-storage devices do not have the ability to accurately detect RFID-tagged items stored within a given container.
Consequently, it is desirable to have a cold-storage apparatus that can detect a relatively high density of RFID-tagged items (including, for example, RFID-tagged items stored in a container) in a ULT environment. Moreover, it would also be desirable to have a cold-storage apparatus that can detect a relatively high density of RFID-tagged items in a ULT environment using an antenna designed to function efficiently at ULT temperature ranges. The antenna may also provide enough RF signal to have the ability to read all RFID tags on a given shelf. Additionally, it would also be desirable to have a cold-storage apparatus that does not require any or extensive user intervention for its operation to, for example, to assess the inventory within while in a ULT environment.